The present invention relates to a system for controlling a flow of fuel vapor discharged from a fuel tank to a fuel vapor storage canister of motor vehicles.
Fuel control systems for controlling a fuel vapor flow discharged from a fuel tank to a fuel vapor storage canister, are well known. One example of such fuel control systems includes a check valve connected with a fuel tank having a filler tube. The check valve is mounted on near an inlet opening of the filler tube through which liquid fuel is supplied to the fuel tank. The check valve is adapted to be operated by insertion of a filler gun into the inlet opening of the filler tube for controlling a fuel vapor flow discharged from the fuel tank to a fuel vapor storage canister.
Japanese Utility Model Application First Publication No. 1-96336 discloses a fuel control system including a check valve mounted on an upper inlet portion of a filler tube of a fuel tank. The check valve is connected via a first fuel vapor tube with the fuel tank and via a second fuel vapor tube with a main canister. The check valve is also connected via a first vent tube with the fuel tank and via a second vent tube with a subsidiary canister. When a filler gun is inserted into an inlet opening of the filler tube, the check valve operates to prevent fluid communication between the first and second vapor tubes and allow fluid communication between the first and second vent tubes. When the filler gun is not inserted into the inlet opening of the fuel tank, the check valve operates to prevent the fluid communication between the first and second vent tubes and allow the fluid communication between the first and second fuel vapor tubes.
U.S. patent Ser. No. 5,099,880 discloses a fuel vapor venting control valve assembly including a check valve. The check valve has a valve seat, a valve element cooperating the valve seat, and a spring and a diaphragm which bias the valve element to be moveable between a flow-blocking position and a flow-delivery position.
An object of the present invention is to provide a valve assembly serving for effectively controlling a fuel vapor flow discharged from a fuel tank to a fuel vapor storage canister, and a fuel control system having an increased operating performance.